edu.umd.cloud9.example.simple
Class DemoWordCountJSON

java.lang.Object
  org.apache.hadoop.conf.Configured
      edu.umd.cloud9.example.simple.DemoWordCountJSON

All Implemented Interfaces:

Configurable, Tool

public class DemoWordCountJSON
extends Configured
implements Tool

Demo that illustrates use of JSONObjectWritable objects as intermediate keys in a MapReduce job. This Hadoop Tool takes the following command-line arguments:

• [input-path] input path
• [output-path] output path
• [num-reducers] number of reducers

Input comes from a flat text collection packed into a SequenceFile with DemoPackJSON. Output shows the count of words on even- and odd-length lines.

Format of the output SequenceFile: The key is a JSON object. The field named "Token" contains a word and the field named "EvenOrOdd" indicates whether the word was found on a even-length or odd-length line. The value is the count of the word on either even- or odd-length lines.

Author:

Jimmy Lin

See Also:

DemoWordCountTuple1, DemoWordCountTuple2

Nested Class Summary

static class

DemoWordCountJSON.MyKey

Constructor Summary

DemoWordCountJSON()
Creates an instance of this tool.

Method Summary

static void	main(String[] args) Dispatches command-line arguments to the tool via the ToolRunner.
int	run(String[] args) Runs this tool.

Methods inherited from class org.apache.hadoop.conf.Configured

getConf, setConf

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.hadoop.conf.Configurable

getConf, setConf

Constructor Detail

DemoWordCountJSON

public DemoWordCountJSON()

Creates an instance of this tool.

Method Detail

run

public int run(String[] args)
        throws Exception

Runs this tool.

Specified by:

run in interface Tool

Throws:

Exception

main

public static void main(String[] args)
                 throws Exception

Dispatches command-line arguments to the tool via the ToolRunner.

Throws:

Exception